Mechanism for truing and dressing grinding wheels



Nov. 17, 1931. F. J. HOHNHORST 1,331,913

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS Original Filed Jan.51. 1927 Iig. 4-

15 latter:

25 tool.

Patented Nov. 17, 1931 UNITED STATES PATENT' OFFICE FERDINAND J.HOHNHORS'I, OF CO'V'INGTON, KENTUCKY MECHANISM FOR TRUING AND DRESSINGGRINDING WHEELS 1 Original application filed January 31, 1927, SerialNo. 164,830. Divided and this application filed October My inventionrelates to mechanism for truing and dressing grinding wheels, such asemery wheels employed in machinery for grinding or polishing surfaces ofmetal in precision grinding, and employing a rotary abrading part fortruing or dressing the grinding wheel. i

It is the object of my invention to provide novel means whereby tosecure the rotary abrading part to its holder and for releasing therotary abrading part from its holder, and the invention will be furtherreadily understood from the following description and claims, and fromthe'drawings, in which line 22 of Fig. l, and partly broken away.

Fig. 3 is an end elevation of my improved device, partly broken away,and viewing the interior of the chuck; and a Fig. 4 is a perspectiveview of the'releasing This application is a division of my applicationfor patent on improvements in mechanism for truingand dressing grindingwheels,

filed in the United States Patent Oflice J anuary 31, 1927, as SerialNo. 164,830, issuedas Patent No. 1,708,575, April 9, 1929.

My invention'is exemplified as employed in connection with. a so-calledgrinding or polishing machine employing a rotary grinding wheel 11 foreffecting the grinding or polishing. t i a The grinding or polishingmachine may be of any suitable or ordinary construction, and may forexample comprise suitable means, such as usual centers, for supportingthe work during the grinding, and be provided with a table 12, pivotallymounted by a pivot 13 on a saddle 14, which has lateral reciprocatingmotion imparted thereto by power means in Y usual manner, as by a pinion1 5, suitably driven, meshing with a rack 16 extending lengthwise of thesaddle and fixed to the saddle. The saddle is slidable on guideways 17,

18, on the frame 19 of the machine. The grinding wheel 11 is Suitablyfixed to the grinding wheel and of grinding surface of the grindingwheel. It

engaged edge 38 of the adapter plate, and

Serial No. 314,141.

a shaft 21 journaled in bearings of a slide 22, adjustable toward andfrom the work-table 12 by any suitable means, the adjusted slide beingarranged to be clamped by suitable means to the frame 19. The grindingwheel is rotatable by suitable power means.

I have instanced the abrading part as acting on the grinding wheelduring the absence of work between the usual centers of the machine.

The rotary abrading part is exemplified as an abrading nib, stub orpencil 25, hereinafter referred to as a nib. Theabrading nib ispreferably of a texture harder than substantially smaller diameter thanthe diameter of the grinding wheel on which it operates. The abradingnib is exemplified as presented end- Wise to the grinding wheel to coactwith the w is shown provided with an axial bore 26,

which coincides with the axis of rotation of the abrading nib.

The abrading nib is shown received in a chuck 27, which is part of orrigidly secured to a spindle 28. Thespindle is ournaled in suitablemanner in a barrel 31, shown as part of a frame 32 which comprises abase 33, suitably secured to an adapter plate 34,

adj ustably positioned lengthwise of the table 12. The base 33 isprovided with a lug 35 along one of its edges, shaped tomatch an engagededge 36 of the adapter plate. A clamping finger 37 coacts with the otherisanchoredon a lug 39 on the base, for providing a space 40 between theclamping finger and the rear end of the base. A clamp bolt 41 isreceived through a hole in the clamping finger and is threaded into athreaded hole 42 in the base for clamping the base to the adapter platein suitable positionsalong the adapter plate. The spindle 28 is providedwith an enlargement 45, at the outer end of which there'is a shoulder46, formed between the enlargement 45 and the chuck 27. The barrel 31 isprovided with an'internal annular rabbet 47. "A ball-bearing 48 islocated between saidenlargement andthe wallsof said rabbet, m

the nib, is normally quiescent.

and is preferably a radial and end thrust ball-bearing. The innerraceway 49 of this ball-bearing is positioned on the enlargement by theshoulder 46. The outer raceway 50 of said ball-bearing is positioned inthe annular rabbet 47, the inner end of said raceway being held by theshoulder 51 form ing the inner wall of said annular rabbet.

There is a ball-bearing between the other end of said spindle and saidbarrel, similar to the ball-bearing iS but reversely positioned inan'enlargement 52 of the barrel.

There is a space, indicated generally at 55, extendingthroughout thebarrel and be tween the balls and raceways of the ball.- bearings,forming a lubricant space which may be filled with lubricant, forinstance a heavy oil, so that all moving parts in the barrel may bethoroughly lubricated. The lubricant may be supplied through a usuallubricant nipple 56 secured to a cap 57 at the outer end of the barreland communicating wit-l1 said space. A washer 58, which may be ofabsorbent material, is located between the chuck 27 and the adjacent endof the barrel.

The rotary abrading part, exemplified as imparted to the abrading nib bycontact with the rotating grinding wheel. The abrading nib is presentedtoward the grinding wheel in such relation'as to cause coaction betweenthe abrading nib at one sideof its axis of rotation and the rotatinggrinding wheeh The rotary abrading nib is preferably pro '62 ofmachineable vmaterial, for instance Babbitt-metal, which is poured ormolded about the shank so as to have fixed relation thereto and to forma stem, by means of -which the nib may be readily held in the chuck.

The means for securing the nib in the chuck are in the presentexemplification shown as comprising a socket 63 in the chuck, which hasan inwardly contracting tapering wall, the outer periphery of the collar62 about the shank being similarly tapered, and being complemental tothe inner tapered wallof the socket of the chuck, for forming intimateconnection therewith, and for clampingly holding the abrading nib in thechuck. When Rotation is.

the abrading nib is firmly seated in the chuck, there is stillpreferably an annular space 65 between the annular shoulder 66 at theinner end of the rotary nib and the outer end of the wall of the socketof the chuck.

In order to provide maintenance of rotation of the rotary abrading partand smoothness of operation and accurate work between it and thegrinding surface of the grinding wheel, a flywheel effect is providedfor the chuck, instanced as an enlargement of the chuck, as by providinga flywheel collar 67 for the chuck. 3 This collar has a rearward annularextension 68 received about the stationary tubular end 69 of the barrel31 and the bearing 48 in said barrel. This tubular end may be providedwith an annular groove 70 for oil or as an air-cushion.

The collar is received about the chuck and is rigidly secured thereto.by providing the collar with an internal slightly inwardly tapered bore75, preferably terminating at. a shoulder 76, and by providing the outerface of the chuck with a complemental tapered outer periphery 77. Thecollar is received about the chuck and the chuck firmly wedged thereinto form a rigid structure.

Means are provided for readily releasing the rotary abrading nib fromits chuck, instanced as accomplished by an extractor plate 81, providedwith a central threaded bore 82. An extractor bolt 83 is threaded insaid here, and is arranged to be resisted by the inner Wall 84 of thechuck socket. vided with the axial bore 26, so as to avoid the formationof a hump or point of resist- The extractor plate is axially movable inthe inner socket portion 85 of the chuck, which is preferablycylindrical. The exitractor bolt is provided with a socket 86,

which is formed in cross-section so as to receive and be turned by asuitable tool, exemplified at 87. The coacting faces of the wrench andsocket 86 are shown polygonal in cross-section. The shank of the wrenchis received through the bore 26 in the abrading nib for coaction withthe extractor bolt, and the extractor bolt is turned with relation tothe extractor plate, for moving the extractor plate away from the bottomof thesocket, for exerting extracting force upon the abrading nib in thesocket, for removing the abrading .nib from the socket. Upon extractionof the abrading nib, the extractor plate is again moved toward thebottom of the clutch socket out of the way of the nib to be placed inthe clutch socket. I Y

Relative rotation between the extractor plate and the clutch isprevented, for instance by means of retaining screws 91 received throughholes in the extractor plate and threaded in the bottom of the socket ofthe chuck, these retaining screws being provided with heads normallyreceived in enlarge- .ments 92 of the holes in the extractor plate Thisis effectedfor maintaining the etxraction plate in the socket.

The combined chuck and fiy-wheel is pref erably provided with radialholes 93, for receiving a suitable spanner wrench, for holding the chuckagainst rotation during rotation of the extractor bolt for moving theextractor plate.

Having thus fully described my invention, What I claim as new, anddesire to secure by Letters Patent, is:

1. In mechanism of the character described, the combination with anend-contact rotary abrading nib, of a chuck provided with a socket inwhich said rotary abrading nib is received, an extractor plate in saidsocket, means for urging said extractor plate outwardly, for releasingsaid abrading nib, means retaining said extractor plate in said socket,said rotary abrading nib having an axial bore adapted to have a toolinsertible inwardly thereinto for coaction with said means for urgingsaid extractor plate outwardly for releasing said abrading nib.

2. In mechanism of the character de scribed, the combination with anend-contact rotary abrading nib having a central bore, of anib-receiving chuck comprising a chuck socket having an inner wall,having an outer tapered portion and an inner cylindrical portion, anextractor plate in said cylindrical portion of said socket, a threadedplug in line with said central bore having operative connection withsaid extractor plate and with said inner wall and arranged by rotationthereof to force said nib outwardly and there by extract the same fromsaid socket, said central bore adapted to receive a tool through itsouter end arranged to coact with said threaded plug for rotating saidplug, and means retaining said extractor plate in said cylindricalportion.

3. In mechanism of the character described, the combination with anend-contact rotary abrading nib having an axial bore, of a nib-receivingchuck comprising a chuck socket having an inner Wall, an extractor platein said socket, a threaded plug in line with said bore having operativeconnection with the axial portion of said extractor plate and with saidinner wall and arranged by rotation thereof to force the nib outwardlyand thereby extract the same from said socket, said bore adapted toreceive a tool into coaction with said threaded plug for rotating saidplug, and means for restricting rotation of said extractor plate in saidsocket to force relative rotation between said threaded plug and saidextractor plate.

4. In mechanism of the character described, the combination of a chuck,and a rotary abrading nib having an end-contact abrading face and atapered holding end, said chuck having a tapered socket in which saidtapered holding end is clampingly received, means between the bottom ofsaid socket and said tapered holding end comprising an extractor platecoacting with the inner end of said nib and a bolt threaded in the axialportion of said extractor plate coacting with the bottom of said socketfor forcing said tapered holding end outwardly in said socket to releasesaid abrading nib, said bolt having a recess adapted to receive anextracting tool, and said rotai abrading nib having an axial bore inwhic said tool is adapted to be received for coaction with saidlastnamed means, said bolt being of greater diameter than said bore andsaid recess being of less diameter than said bore, for forcibleextraction of the clamped tapered end of said rotary abrading nib fromsaid tapered socket.

5. In mechanism of the character described, the combination of a chuck,a rotary abrading nib having an end-contact abrading face and a taperedholding end, said chuck having a tapered socket in which said taperedholding end is clampingly received, a nibextract-ing part in said socketarranged to act on said nib axially to push said nlb forcibly outwardfrom its clamped relation in said socket to release said nib, retainingmeans retaining said nib-extracting part in said socket, said rotaryabrading nib provided with an axial bore, through which a a 5 tool isadapted to be received for coact-ion with said nib-extracting part forextracting said nib.

In testimony whereof, I have hereunto signed my name.

FERDINAND J. HOHNHORST.

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